Apparatus for burning solid carbonizable fuels



May 23. 1933. F M BLAI 1 1,910,233

APPARATUS FOR BURNING SOLID CARBONIZABLE FUELS Filed July 15. 1950. 3 Sheets-Sheet 1 F rcmKMJBlair May 23, 1933. F. M. BLAIR 1,910,233

APPARATUS FOR BURNING SOLID CARBONIZABLE FUELS Filed July 15, 1950 3 Sheets-Sheet 2 QSE EQ l gin mute? FFGIIKMBIGH May 23, 1933. F. M. BLAIR 1,910,233

APPARATUS FOR BURNING SOLID CARBONIZABLE FUELS Filed July 15, 1950 3 Sheets-Sheet 3 f ,6, Fran k M.Bluir Patented May 23, 1933 PATENT OFFICE smmx M. 3mm, or cowmaus, omo

APPARATUS FOR BURNING- SOLID GABBONIZABLE FUELS Application filed iFuIy 15,

tends from the discharge end of the maga-i zine into the interior of the furnace and in which conduit there is provided a movable conveyor for advancing the coal, as needed and in a regulated manner, from the magazine through the conduit, the inner end of said conduit terminating in an open topped feeding bowl disposed substantially 0611-1,

trally within the combustion area of the furnace and provided with surfaces arranged to receive the coal as the latter is automatically discharged over the open upper edges of the feeding bowl and on which surfaces and over the feed bowl active combustion of the fuel takes place.

It is an outstanding object of the present invention to form the feeding bowl of automatic stoker apparatus of the character described with spaced substantially vertical side walls between which an air receiving chamber is provided adapted for the reception of air from a fan or other suitable sources of supply and wherein the inner wall of the feeding bowl is provided with a plurality of minor orifices throu h, which air from the air chamber is passe to penetrate the body of coal passing substantially upwardly through the feeding bowl and thence over the upper edges of said bowl onto the combustion surfaces surrounding said bowl and located. below the upper edge of the bowl, the air supplied through said minor orifices being controlled in volume to produce a slow rate of combustion in said coal to drive off the more volatile content thereof prior to the discharge of the coal from the feeding bowl and the reception of the coal or coke on the combustion surfaces, the outer walls of the feeding bowl being provided with major orifices arranged to direct streams of air outwardly and to dis 1930. Serial No. 468,066.

seminate the oxygen content thereof throughout the mass of coal or coke supported by said combustion surfaces to the end of obtaining very complete combustion of the solid fuel to obtain its maximum heat producing values and to minimize the formation of cinders, clinkers, ash and other waste products, as well as to minimize the production of smoke and fuel waste.

It is another object of the invention to arran e the orifices in the said walls of the fee 'ng bowl or tuyere so that said orifices slope substantially downwardly to prevent the accumulation of tar or other clogging deposit in such openings or orifices, even when low air pressures are provided.

In order that the invention may be more fully'understood, reference is to be had to the accompanying drawings, forming a part of the specification, in which:

Figure 1 is a view in vertical cross-section takenthrough a furnace equipped with the automatic stoker apparatus comprising the present invention,

Figure 2 is a horizontal sectional view taken through the furnace, on the plane indicated by the line 2-2 of Figure 1 and illustrating the stoker apparatus in plan,

Figure 3 is an enlarged vertical sectional view taken through the feeding bowl or so tuyere,

Figure 4 is'a side elevation of the feeding bowl or tuyere,

Figure 5 is a transverse sectional view taken through a furnace provided with a slightly modified form of feeding bowl or tuyere, and

Figure 6 is a side elevation of the apparatus disclosed in Figure 5, the furnace wall being shown in vertical cross-section.

Referring more particularly to the 'drawings, the numeral 1 designates a furnace consisting of front and rear walls 2 and 3 respectively, united by means of vertical side walls 4 to produce a combustion zone 5. The front wall is provided with an opening providing access from the exterior of the furnace to the combustion zone and which opening is normally closed by a removable clo-- sure 6. The bottom of the combustion zone is provided with refractories 7 having inwardly and downwardly sloping up er sur-- ber 12 formed with an opening which is normally closed by a, swinging lid 13. The cover member is substantially square when viewed in plan in order that 1t may be positioned on the top of the magazine so as to secure various desired workin positions on the part of the lid 13, pernuttin coal to be fed into the magazine either om the front 9r sides thereof. The ma azine is adapted to contain coal of small or fine sizes which is fed by gravity into the forward portion of the conduit 10.

Arranged within the conduit is a helical conveyor 14 which carries an axial shaft 15 suitably journaled for rotation in bearin 5 carried in conjunction with the opposite en s of said conduit. The forward end of the shaft 15 is equip d with a worm gear 16, which me'shes w1th.a worm 17 driven by means of the shaft 18 by an electric motor 19. The shaft 18 .also drives a blower or .fan 26 which draws air from the atmosphere and delivers the same under pressure for passa e through an air conduit 21-leading into t e casing 9.

By this auxiliary mechanism, coal is ad-.

vanced longitudinally through the conduit 10 and thence throu h the upturned discharge end of the 'comfuit arranged centrally in the combustion zone.

Resting on the upper edges of the casing 9 and't e upturned d scharge end of the conduit 10 1s a feeding bowl or tuyere 22. This unit is preferably formed from a sin le metallic casing of substantially circ ar form, as indicated, although it may possess other desired configuration, 'such as an oval or rectangular outline and may be, if desired, com used of a number of sectional units or bloc grouped together to constitute a bowl or frame. the form of the invention disclosed in Figures 3 and 4, the feeding bowl or tuyere is of a circular formation when viewed in plan and comprises inner and outer spaced concentrically arranged walls 23 and 24 respectivel which are joined by means of a top wa l 25 which slopes downwardly and outwardly. The inner wall 23, contiguous to the top wall 25, is provided less.

with a plurality of orifices 26 each of which is substantially rectangular in configuration. In vertical cross-section, however, these orifices include spaced air inlet and outlet portions 27 and 28, respectively, which are arranged in different planes and are united by inwardly and downwardly extending portions 29. The shaft'of these orifices, therefore, is such as to minimize the liabilit of the same becoming clogged or obstructe by coal, tar or other material contained in the fuel which advances generally upwardly through the tuyere. The outer'wall 24 of the tuyere is provided with a plurality of rows of orifices 30 which possess reater effective areas for the passage of alrithan the outer area of the orlfices 26, in order that the major portion of the air delivered to the casing 9 by the fan 20 may be directed outwardly from thetuyere through the major orifices 30, a lesser volume or quantity of such air being passed through the secondary orifices 26. The inner wall 23 of the tuyere is also inclined or flared in an outward and upward direction to facilitate the passage of coal through the tuyere and the subsequent passage of the coal over the top wall 25 and thence upon the combustion supporting surfaces 8. The surfaces 8 are im rforate and the air used in producing and effecting thorough combustion is obtained directly from the fan 20 through the.

orifices 26 and 30.

' -In operation, the fine coal, which is usually employed in stokers of this character, is fed upwardly through the ,feeding bowl or tuyere into the combustion zone 5 of the furnace. As the coal nears its combustion zone the temperature thereof is progressively raised. Air is first passed through the coal by way of the orifices 26, the said air bein delivered inwardly of the progressively a vancing. upwardly moving body of coal. Suflicient oxygen is thus admixed with the coal to effect low temperature combustion thereof, that is, the release of the volatile content of thefuel such as gas and liquids and other low temperature combustion substances. This reduces the coal to a coke-like condition and it is then delivered to the combustion. surfaces -8 and thoroughly intermingled with the air passing outwardly and radially from the orifices 30 where final combustion of the fuel takes place. In practice, it has been found that this combustion is .very thorough and substantially smoke- The impurities of ash present following combustion tends to agglomerate in the form of clinkers which at infrequent intervals may be removed from the combustion surfaces bythe removal of the closure 6. It is, of course, within the scope of the present invention to provide a thermostatic switch (not shown) for controlling the operation of the electric motor 19, especially whenthe stoker is used in the heating of residences and the like where it is necessary to maintaln a substantially uniform or desired tempera ture.

In the form of the invention depicted in Figures 5 and 6, a feeding bowl or tuyere 31 is disclosed having an inner wall 32 which constitutes the'upturned discharge end of the conveying conduit 10. In this form of the invention, the wall 32 is of imperforate construction. The upper portion of the wall 32 terminates in an enlarged outwardly directed lip 33 which registers with a perfo rate outer wall 34. The perforations 35 in this wall, through which the air passes in an outward and radial direction, are ranged above stepped combustion supporting surfaces 36 formed in connection with an imperforate plate 37 The outer edges of the plate 37 are supported by means of ledges 38 projecting from the furnace walls 39, while the inner edges of the plate 37 engage with brackets 40 carried by the wall 32. The brackets 40 also serve to effect the support of the perforate outer wall 34. An air supply conduit 41 passes through one of the furnace walls to provide for the forced circulation of air in an outward and radial direction from the perforations 35. In order to effect complete combustion of the fuel supported by the surfaces 36. The apparatus shown in Figures 5 and 6 is especially adapted for installation in large furnaces, such' as steam boiler furnaces or other furnaces requiring a high rate of heat output. A fan 20' communicates, as usual, with the air supply conduit 41.

From the foregoing it will be seen that the present invention provides automatic stoker apparatus by which asolid carbonizable fuel is automatically fed to the combustion zone of a furnace and wherein the fuel is first subjected to low temperature carbonization and thence finally to active combustion by passing through said fuel' regulated quantities of air so directed as to secure the desired degree of combustion. The arrangement provides for the complete utilization of the fuel and the liberation of its heat units with slight production of ash or waste products. Moreover, high temperatures are obtained in the furnace without any destruct ve action to that portion of the stoker consisting of the tuyere and combustion supporting surfaces arranged 'in the furnace. The apparatus is essentially simple and when the proper grade of fuel is used in connection therewith, the apparatus is both durable and reliable and not likely to become out of order.'

That is claimed is: I

1. In combination, a combustion chamber having side walls and an imperforate fuel supporting surface and fuel feeding means including a centrally disposed fuel feeding and tuyere structure extending upwardly through and terminating a substantlal distance above the adjoining portion of the said surface comprising spaced annular side walls and a top wall closing the top of the cham: ber formed therebetween, the inner wall defining a vertical fuel passage, means for feeding fuel upwardly through said passage and onto the fuel supporting surface, which slopes uniformly upwardly from the tuyere structure to the said side walls, a ertures 1n the said annular side walls for eeding air inwardly into the fuel passage adjacent the top thereof and outwardly over the said surface, and means for delivering air to the said chamber.

2. In combination, a combustion chamber having side walls and an imperforate fuel supporting surface and fuel feeding means including a centrally disposed fuel feeding and tuyere structure extending upwardly through and terminating a substantial distance above the adjoining portion of the said surface comprising spaced annular side walls and a top wall closing'the top of the chamber formed therebetween, the inner wall defining a vertical fuel passage, means for feeding fuel upwardly through said as sage and onto the fuel supporting sur ace, which slopes uniformly upwardly from the tuyere structure to the said side walls, apervtures in the said annular side walls for feeding air inwardly into the fuel passage adjacent the top thereof and outwardly over the said surface, the apertures in the outer of the said annular side walls being arranged in rows and extending over substantially the full height of the said wall, and means for delivering air to the said chamber.

3. In combination, a combustion chamber having side walls and an imperforate fuel supporting surface and fuel feeding means including a centrally disposed fuel feeding and tuyere structure extending upwardly through and terminating a substantial distance above the adjoining portion of the said surface comprising spaced annular side walls and a top wall closing the top of the chamber formed therebetween, the inner wall defining a vertical fuel passage, means for feeding fuel upwardly through said passage and onto the fuel supporting surface, which slopes uniformly upwardly from the tuyere structure to the said side walls, apertures in the said annular sidewalls for feeding air inwardly into the fuel passage adjacent the top thereof and outwardly over the said surface, said apertures sloping downwardly and outwardly away from the said chamber, and

means for delivering air to the said chamber.

In testimony whereof I affix my signature.

FRANK M. BLAIR. 

